Can the Stealth IIgs kit be installed in a “Platinum” IIe case, so as to include the numeric keypad on the built-in keyboard? In short, I'm asking if the “Stealth IIgs” baseplate is mechanically compatible with the “Platinum IIe” top-case.
Can always paint it I assume?Yes, you can. The baseplate used for the Stealth GS kit is for the later //e cases that don't use the "velcro" tabs for the case lid. I owned an early //e that I had upgraded to the IIgs upgrade kit. Case had to be replaced with one from a 1984-86 //e to work with the baseplate. So, you'll be fine using the Platinum IIe "Extended" upper case with the Stealth GS baseplate. It won't be the right color, but that's ok.
And can the AppleColor 100 monitor handle the output from the IIgs's RGB port?
If you wanted. You'd have to redo the icons on the rear panel in black, so they'd be visible again. Unlike the ones on a real IIgs or a Mac, they aren't molded, instead being painted, like on the regular IIe.Can always paint it I assume?